Pneumatic hydraulic riveting tools are one example of tools which undergo extreme amounts of shock and vibration during use. Other tools include manual riveters and manual and power operated staplers and nailers. Extreme amounts of vibration and shock also occur in drills and other non-fastener devices.
The vibrations and shocks that pass through these tools affect the individual components which are mounted on one another. Because the tools are not molded from a single piece of material, there is no uniform vibration of the components. Therefore, the components are pushed together and pulled apart during each use. With repeated use, the threads may bend, break, or otherwise become damaged.
No satisfactory shock absorber has heretofore been available for high vibration power tools. One must simply rely on the tight engagement of components to prevent damage to the tool. Maintenance of these devices requires frequent checking and periodic tightening of the components. Especially in threaded engagements, severe vibrations or shocks frequently cause damage to the components requiring their replacement, if not the entire tool. The use of lock washers to prevent damage has proved unsatisfactory.
Experiments have found that rivet tools without one or more shock absorbers and which has not been subject to periodic tightening exhibit damaged threads after approximately 5,000 uses.
An inexperienced user may not check the rivet gun as often as recommended. Therefore, maximizing the number of uses before potential thread damage may occur is most desirable as it would increase the life of the components of the tool.